'use strict';
function make_multidimensional_to_one(collection){
  collection=(collection+"").split(",");
  collection=collection.map(function(x){
    return Number(x);
  });
  return collection;
}
function double_to_one(collection) {
  let result=make_multidimensional_to_one(collection);
  console.log(result);
  return result;
}

module.exports = double_to_one;
double_to_one([1, [2], [3, 4]]);
